1. Field of the Invention
The present invention pertains to containers in the form of a sealed tub, and in particular to such containers for use with products which cannot be readily poured out of an open top container.
2. Description of the Related Art
Specialized containers have been developed for materials which are difficult to dispense if the use of external implements, such as spoons, is to be avoided. For example, ice cream confections have been produced in a cylindrical form, shipped inside cardboard tubes for delivery to consumer. When the outer wrapping is removed from the cardboard tube, a spoon could be used to withdraw the ice cream confection in the amount desired. However, specialized containers have been developed with a plastic plunger fitted to the bottom end of the tube. With operation of the plunger, a consumer can push a desired amount of ice cream confection past the top of the tube, and can continue the process in virtually any increment size desired, until the entire contents of the tube are consumed. A package of this general type has been proposed for cheese foods, as described in U.S. Pat. No. 2,270,935. The tube-and-plunger concept has also been proposed for toothpaste, shaving cream and the like, as described in U.S. Pat. No. 2,434,505.
Containers have also been proposed to provide a plunger action without requiring a separate plunger element, and examples may be found in U.S. Pat. Nos. 2,853,209 and 4,394,906.
It is sometimes desired to dispense the entire contents of a container in a single operation and U.S. Pat. No. 3,483,908 has proposed a plastic container having a flexible bottom wall which applies a displacing force to the cupcake. Further advances are still being sought in the container art, particularly for products such as food which must be carefully sealed, with the integrity of the seal being maintained until final delivery to a consumer.